ZnDiy-BRY PC4-02 3D Printer 1/4" PT Male Thread 4mm Push-In Pneumatic Connectors - Golden (5 PCS)
Designed for polyurethane or nylon tubing; The direction of the tube can be changed freely even installed; Elliptical release ring help to connect to tube easily by manual no special tools required; Outside (and inside where applicable) hexagonal wrench tightening.